1. Field of the Invention
The present invention relates to an optical position detecting unit and an optical coordinate input unit formed by using the optical position detecting unit. In the optical position detecting unit, an image pickup device having a pixel array region, such as a charge coupled device (CCD) image sensor, is used so that not only the number of pixels in the image pickup device can be reduced but also the detecting resolution thereof can be improved.
2. Description of the Related Art
As a conventional optical position detecting unit, there is known a configuration which includes an image pickup device (such as a television camera or the like) having a pixel array region (image pickup region) constituted by a plurality of pixels and a movable body having a point-like light source. In the configuration, the image pickup device picks up an image of the light source of the movable body to obtain an image pickup signal so that the position of the movable body is measured optically through image processing of the image pickup signal. A CCD image sensor is used as the image pickup device.
In order to improve the accuracy of a position measured by the conventional optical position detecting unit, it is necessary to improve the resolution of the image pickup device. In order to improve the resolution of the image pickup device, it is necessary to increase the number of pixels in the CCD image sensor greatly. However, it is difficult to increase the number of pixels in the CCD image sensor greatly because a manufacturing cost rises.